The Premier League giants have both been linked with the World Cup-winning star in recent times, amid rumours that he could be available at the end of the season.
Now it is understood that Barca are looking to sell their man, which could kick both sides into action.
Fabregas is seen as one of Spanish football’s top names and has been a regular at the Nou Camp under Tata Martino this term – making 42 starts.
But with the current Barcelona chief looking as if he could leave in the coming months, there is likely to be a period of great change at the Catalan club.
With Fabregas entering the final two years of the contract, now is believed to be seen as a good time to sell by the La Liga champions.
United made several attempts to snap up the 26-year-old last year, but were ultimately unsuccessful.
They are rumoured to have since remained keen, and could look to reignite their pursuit of his services should he be made available to them – as reports indicate he has at an informal level.
Arsenal might also make a swoop for their former idol, who carved out his reputation in north London after leaving Barca to join the Gunners as a teenager.
Fabregas is likely to be valued at upwards of £25m.